Version 2 Table Project Guidelines

Rules for Review and Assignment of V2.x Tables

The source of truth for the table content is in the chapters, which is considered Normative. The appendices are considered Informative, and so is the v2 data base.

HL7 V2 Tables and HL7 V3 Concept Domains

1. The name of every HL7 V2.x table will represent the name of a HL7 V3 Concept Domain. HL7 V3 Concept Domains will be created with names as similar as possible to their corresponding Version 2 artifacts. (9-June-2011 Minutes)
2. HL7 V2.x "User" tables with No Suggested Values will be represented as a Concept Domain only (no code systems or value sets). (7-July-2011, 9-June-2011 Minutes)
3. The name of the new concept domains should be the same as the table name with spaces removed and in upper camel case if there is no collision with a pre-existing v3 Concept Domain.
4. If there is a collision, group needs to agree on a process to ensure no collision.

HL7 V2 Tables and HL7 V3 Code Systems

1. Every V2 table is uniquely identified by the Table Number which is consistent across all versions of V2 publications. (27-Sept-2013 minutes)
2. HL7 V2.x Tables that have associated values that are HL7 authored and published in an HL7 V2 Standard will be HL7 V3 Code Systems. (9-June-2011 minutes, 27-Sept-2013 minutes)
3. Every v2 table is either an "HL7 Table" or a "User Defined Table". Every "HL7 Table" will be one or more code systems Every "User Defined Table" that has suggested values enumerated will be one or more code systems. (7-July-2011 minutes)
4. HL7 V3 code systems that are created from the enumerated values of V2 code tables will be registered as Type 18 OIDs. (9-June-2011 Minutes)

New HL7 V3 Code Systems

Glossary

• semantic boundary: [to be defined] (27-Sept-2013 minutes)

Rules

1. Any change to the semantic boundary of an HL7 V2 table will result in a new HL7 V3 Code System. (9-June-2011 Minutes, 27-Sept-2013 minutes) This will result in having multiple HL7 V3 code systems that correspond to a single V2 table. (23-June-2011 minutes). Example: A specific V2 table in publication 2.3.1 may not be the same V3 code system as the same V2 table in publication 2.4. (27-Sept-2013 minutes)
2. If the representation of a coded concept changes in a table (e.g. numeric to alphanumeric) in a HL7 v2.x release such that the ability to trace previous identifier of that concept is not possible, it is a new code system. (24-Jan-2014 minutes)
3. If addition of a new concept changes the meaning of an existing concept in a table whether a code is active or inactive, a new code system is created, not a new version of a code system.(24-Jan-2014 minutes, 23-April-2015 minutes)
4. When codes for Other and/or Unknown are present, if different codes are added in a subsequent version, then there is a NOT new code system, there is just a new Code System Version. Although Other and Unknown have had their meaning changed in the new version, due to our discussions about tables containing the Flavors of Null, the meaning of concepts such as these in v2 are essentially undefined or underspecified. (7-July-2011 minutes) (Flavors of Null discussion on the 2/20/2014 call)
5. When a code system is created the full name will be the name of the table, and the short or symbolic name will be the name of the table with spaces removed, in lower camel case if possible, except if the name collides with a previous code system with the same name. (24-July-2014 minutes)

HL7 V3 Code System Versions

Glossary

• HL7 V3 Code system version: specific persisted state of a HL7 V3 code system (27-Sept-2013 minutes)
• HL7 V3 Code system version identifier: designator of a HL7 V3 code system version (27-Sept-2013 minutes)

Rules

1. In the first HL7 published V2 standard in which a table with values is introduced, the HL7 V3 code system version identifier is "1". (23-June-2011 minutes, 7-July-2011 minutes, 5-Sept-2013 minutes, 27-Sept-2013 minutes)
2. When there is a new version of the HL7 V3 Code System, its HL7 V3 code system version identifier will be incremented by 1. (23-June-2011 minutes,7-July-2011 minutes, 27-Sept-2013 minutes)
3. For any HL7 2.x publication, if the list of values in a particular table is the same as the list of values in the previous HL7 2.x publication, the HL7 V3 code system version remains the same. (23-June-2011 minutes, 27-Sept-2013 minutes)
4. If new values have been added to a table in an HL7 2.x publication that do not change the meaning of any of the existing values in the table, this results in a new version of the HL7 V3 Code System. Note: New additions cannot re-define an inactive code. (23-June-2011 minutes, 7-July-2011 minutes, 27-Sept-2013 minutes, 23-April-2015 minutes)
5. If the list of values in a table in an HL7 2.x publication has new values added as the only change, no change to the meaning of the values that are the same as in the previous HL7 version, there is no new HL7 V3 Code System, just a new version of the HL7 V3 Code System. (23-June-2011 minutes, 27-Sept-2013 minutes)
6. If the encoding of concepts in a particular table changes, there is a new HL7 V3 Code System. (23-June-2011 minutes, 27-Sept-2013 minutes)
7. If a value is removed from a HL7 2.x publication table, then there is a new Code System version (NOT an additional code system). (23-April-2015 minutes)
8. If the meaning of a HL7 2.x publication table value is changed significantly (with the exception of values that are the same as v3 Flavors of Null) then there is a new HL7 V3 Code System. (27-Sept-2013 minutes) (and discussion on 2/20/2014 call)
9. If the content of the HL7 v2.x published table (list of codes) is unchanged across all releases of HL7 V2.x, then there is only one version of one single code system for this table of values. (7-July-2011 minutes)
10. HL7 V3 Code system versions have an effective version identifier, which is the HL7 standard version ID as carried in the message header. Once they have been superseded by a new version, they will also have the retired version identifier. (5-Sept-2013 minutes)
11. If the content of a table in a particular HL7 v2.x release is the same as the content of the same table in the previous HL7 v2.x release, the code system for that table is the same version of the code system for the same table as in the previous HL7 release version. (7-July-2011 minutes)
12. For tables that are essentially different subsets of a larger set of codes (such as the YES/NO/UNKNOWN tables), a new code system containing the comprehensive set of all the codes in this space will be created for the most comprehensive set of all of the codes, and the other tables will be represented as value sets built on the code system with the superset of codes.
13. If there is an editorial technical correction to the print name of a concept that does not result in a change in the meaning of the concept, this does not result in a new version of the code system. (24-July-2014 minutes)
14. If there is a case change in the print name of a concept between Title Case and Sentence Case, or a spelling correction, or a wording a wording change to make grammar or synonyms or language more clear, with no meaning changes, this is considered an editorial technical fix, and does not cause a new version of the code system. (31-Jan-2013 minutes, 26-March-2015 minutes)
15. When a comment states the code is retained for backwards compatibility, it does not trigger a new version of a code system. (26-Feb-2015 minutes)

HL7 V2 Tables and HL7 V3 Value Sets

1. HL7 V2.x Tables that have associated values are HL7 V3 Value Set. (9-June-2011 minutes)
2. The Value Sets defined as "all codes" from the code systems built from the V2 standard tables will be Type 21 OIDs. (9-June-2011 minutes, 22-August-2013 minutes)
3. The Value Sets created will be defined as 'All codes from X' where 'X' is an HL7 Code System created from a table, except where rule 12 above applies.
4. If the code system for a table changes in a new published release of HL7 Version 2.x, a new value set for the table will also be created based on the new code system.

HL7 V2 Tables and HL7 V3 Bindings

1. HL7 V2.x "HL7" Tables have a UV (Universal) binding between the Concept Domain and the Value Set. (9-June-2011 Minutes)
2. HL7 V2.x "HL7" Table bindings have a coding strength of Coded With Exceptions (CWE), with any deviations from this rule explicitly noted (9-June-2011 Minutes, decision on 6-March-2013 call):
3. HL7 V2.x "User" Tables have either a Representative realm (R1) or an Example realm (X1) binding between the Concept Domain and the Value Set. The binding decisions are arbitrary based upon the perception and consensus agreement by the review group of the completeness of domain coverage by the published set of codes. (9-June-2011 Minutes) The preferred or default binding will be Example (X1) unless in the opinion of the tables project group the set of published codes seem to completely cover the domain for all Use Cases, in which case it will be Representative (R1) (decision in the San Antonio WGM January 2015)
4. HL7 V2.x "User" Table bindings have a coding strength of Coded With Exceptions (CWE), with with any deviations from this rule explicitly noted (9-June-2011 Minutes, decisions on 6-March-2013 call):